The present invention relates to an elastic hinge for eyeglasses.
The market currently requires elastic hinges for eyeglasses to allow perfect adaptation of the eyeglasses to the head of the user without any discomfort to the user.
In particular, it is necessary to combine a highly stable positioning of the eyeglasses with an equally highly delicate resting of the eyeglasses against the user""s skin.
Currently commercially available elastic hinges for eyeglasses substantially comprise, at the end of a temple, an elongated hollow body with a flat end which contains a spring arranged between the head of a pivot which passes through it together with a contrast element which is locked in said body.
The pivot, by means of the contrast element, engages therein with a first hinge element, which is in turn pivoted to a second hinge element which is fixed to the front of the eyeglasses.
The second hinge element usually has a polygonal profile in order to define one or more stable operating positions of the eyeglasses.
The components of conventional hinges allow them substantially to be elastic as regards extra-wide opening, which is now commonly provided, in order to both better adapt the fit of the eyeglasses and prevent forces applied to the hinge by the user from damaging its functionality prematurely.
However, fit analysis has shown that it is particularly important for hinges to also allow a preset torsional stroke of the temple with respect to the front of the eyeglasses.
In order to achieve this function, various constructive solutions provide for the addition of one or more elastic elements which are connected to stroke limiting or articulation means, which are meant to allow a connection which can yield elastically and torsionally over a limited stroke of the temple with respect to the front of the eyeglasses.
However, the solutions that have been proposed so far have proved themselves less than fully satisfactory from the point of view of fit.
In particular, a certain concentration (usually in two points) of the load of the temples on the user""s head, consequently generating possible discomfort for the user, has not been eliminated up to now.
The aim of the present invention is to provide an elastic hinge for eyeglasses which solves the above-mentioned drawbacks of conventional models, allowing not only stability of the working positions and of the extra-wide opening but also a torsional movement.
The torsional movement, in particular, must provide for a limited stroke, within a preset limit, of the temple with respect to the front of the eyeglasses, with a consequent resting contact of the temple in at least four points in order to ensure both that the eyeglasses will not move and that the pressure forces are adequately distributed on the head of the user.
Another object of the present invention is to provide an elastic hinge which is particularly strong notwithstanding its substantial constructive simplicity.
Another object of the present invention is to provide an elastic hinge having a reduced number of components.
Another object of the present invention is to provide an elastic hinge whose production costs are competitive with respect to conventional hinges having the same functions.
Another object of the present invention is to provide an elastic hinge which can be manufactured with conventional technologies and equipment.
This aim, these objects and others which will become apparent hereinafter are achieved by an elastic hinge for eyeglasses, characterized in that it comprises a temple which has an end provided with a hollow body which accommodates, with a coupling which allows only rotation, part of a tubular element in which one end of a shaped element is guided with a coupling which allows only sliding, said shaped element forming, at the other end, an eyelet which is inserted between two other eyelets which are fixed to the front of the eyeglasses so as to form the articulation of said hinge, a single spring being fixed with a first end to a part of said shaped element located inside said tubular element, with a second end to said hollow body and with a portion, which is intermediate between said first and second ends, to said tubular element.